Question

Assertion (A) Hydrogen is the first element in the periodic table.
Reason (R) It has electronic configuration $1s^1$.

• A. Both $A$ and $R$ are correct; $R$ is the correct explanation of $A$.
• B. Both $A$ and $R$ are correct; $R$ is not the correct explanation of $A$.
• C. $A$ is correct; $R$ is incorrect.
• D. $A$ is incorrect; $R$ is correct.

Answer 1

Answer: (A)

Hydrogen is the first element in the periodic table as it has the electronic configuration of $1s^1$.
Thus, both $A$ and $R$ are correct and $R$ is the correct explanation of $A$.